Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, February 2001. / Includes bibliographical references. / Experimental phase equilibria, whole rock major and trace element concentrations, and mineral major and trace element concentrations are used to constrain the petrogenesis of high degree, hydrous melts of the mantle, with particular focus on komatiites from the Barberton Mountainland, South Africa. Chapter 1 presents experiments on a Barberton komatiite composition under anhydrous and H20 saturated conditions. A comparison of the compositions of augite in the experiments with augite in the samples indicates that at least 4.5 wt.% H20 was present in the komatiite melts prior to emplacement. The presence of H20 in the magmas would allow them to be produced at lower temperatures than required by anhydrous models of komatiite genesis, and would obviate the need for extremely high temperatures in the Archean mantle. In Chapter 2, ion probe analyses of augite in Barberton komatiites are used to quantify the effects that metamorphism has had on the bulk rock compositions. The results indicate that high field strength elements and most rare earth elements were not significantly mobilized by metamorphism, while Eu and Sr were mobilized. Some Barberton magmas were enriched in light rare earth elements and Sr, and depleted in high field strength elements, which are the chemical characteristics of modem subduction related magmas. Chapter 3 presents melting experiments that explore the effect of H20 on melts in equilibrium with olivine and orthopyroxene at 1.2 to 2.4 GPa. The results of the experiments are used to infer the thermodynamic properties of H20 in silicate melts, and to construct a numerical model that predicts the composition of high degree mantle melts. The model is used to estimate the melting conditions that produced high-MgO andesites, boninites, and komatiites. It is shown that Barberton komatiites can be produced by melting at low pressures (2.4-3.0 GPa) and temperatures (1440-1500 °C). Chapter 4 demonstrates that basaltic komatiites overlap the compositions of modem boninites and display nearly identical trace element systematics. Komatiites are also shown to have numerous chemical similarities to boninites as well. It is proposed that komatiites and basaltic komatiites were produced by the same processes that produce modem boninites. The lack of komatiites in modem subduction zones is attributed to -100*C secular mantle cooling that has occurred since 3.5 Ga. / by Stephen Wayne Parman. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998. / Includes bibliographical references (p. 189-198). / by Rafael Katzman. / Ph.D.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 18). / Soil is Earth's largest terrestrial carbon pool (Oertel et al., 2016) and can act as a net source of greenhouse gases (GHG). However, if organic material accumulates in soils faster than it is converted to CO2 by cellular respiration, soil becomes a smaller GHG source and even has the potential to become a GHG sink. Not much is known about factors that drive soil to be a source or a sink of GHG. Soil temperature and moisture have both been shown to correlate with CH4 emissions and temperature has been shown to correlate with CO 2 emissions (Jacinthe et al., 2015). Currently these relationships are not well constrained, particularly in upland soils, which are soils found at elevations between 100 and 500 m (Carating et al., 2014). Soil from the Harvard Forest was collected and used in two in-lab flux experiments to constrain the effect that soil moisture has on i.) the rate of CH4 and CO2 production/consumption and ii.) the fraction of injected CH4 that is oxidized to CO2 by soil microbes. The first experiment involved injecting vials containing soil samples with CH4 , taking an initial measurement with a residual gas analyzer (RGA), incubating for three days, and taking final measurements using the RGA. The results of this experiment indicated that cellular respiration is an important carbon source in these soils, with more CO2 coming from cellular respiration than from the oxidation of CH4. The second experiment involved injecting vials containing soil samples with CH4 and 14CH4 as a tracer, incubating for six days, and analyzing CO2 from each sample using a scintillation counter. This experiment showed a weak trend indicating that increased soil moisture may result in decreased CH4 oxidation. Results showed that decays per minute from the samples were lower than in a control. These results indicated that not all CO 2 from each sample was successfully captured and analyzed using the methods here. So while the trend may hold true, it should be supported by reconducting the experiment using a more reliable means of CO2 capture. The unexpected results from both experiments indicated that there is still much to be learned about the reactions that occur in these soils and how to perfect laboratory methods to study them. / by Alexa Jaeger. / S.B.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1986. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Bibliography: leaves [66]-[68]. / by Tom W. Rooze. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990. / Includes bibliographical references. / by Geoffrey Alexander Abers. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2003. / Includes bibliographical references (p. 199-205). / Baroclinic eddies are an important component of the General Circulation which regulate the extratropical climate by transporting heat and momentum. An idealization of this feedback is provided by baroclinic adjustment theories (Stone, 1978), which envision a linearly neutralized mean state. Based on the Charney-Stern condition, most baroclinic adjustment formulations propose basic states with homogenized potential vorticity. In this thesis we investigate the degree of potential vorticity homogenization in the extratropical troposphere. We show that homogenization is only observed across a shallow region around 700 mb, and propose an adjusted state with homogenized PV at the steering level alone. We demonstrate that this state can be neutral under certain conditions, and investigate its relevance for the equilibration of an idealized model. Because of the role of the PV flux as an eddy forcing of momentum, it is illuminating to describe the equilibration in terms of the redistribution of momentum. This affects both the PV gradient and the steering level of the waves, but the condition of homogenization at the steering level is very robust. In the 2D problem, a local balance can be written between the dynamical and frictional forcing of momentum. However, in the 3D problem there is an additional redistribution by a remotely forced meridional circulation. To circumvent this difficulty, we have developed a momentum-based formulation that exploits the interchangeability of momentum and temperature for quasi-balanced stratified rotating flow. By rewritting the thermodynamic equation as a momentum equation, we eliminate the forcing by the mean meridional circulation and formulate a local balance between the eddy PV flux and the non-conservative forcing of momentum. / (cont.) This introduces a new variable, which we call potential momentum. The circulation can then be described in terms of the conversion between potential and physical momentum. A major simplification of this formulation is that temperature and momentum can be directly compared. For instance, the surface temperature gradient appears as a momentum source, which helps ellucidate the role of the momentum fluxes and the so-called "barotropic governor" (James, 1987) for the baroclinic equilibration. Our results suggest that mechanical friction might prevent thermal homogenization at the surface. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990. / 1 folded map in pocket. / Includes bibliographical references (leaves 190-196). / by Laurence M. Page. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996. / Folded maps in pocket following text. / Includes bibliographical references. / by Clyde J. Northrup. / Ph.D.

Thesis: S.M. in Geophysics, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 65-69). / Reservoir models use the elastic moduli of rock, both bulk and shear, to compute deformation. These moduli may change with pressure and fracture density, but this effect is usually left out of models. This work shows effective elastic moduli of fluid-filled fractured rock through a self consistent method. The calculated effective elastic moduli for a penny-shaped crack are compared to literature values. Effective moduli values for rocks containing rough fractures with asperities are presented. The bulk and shear moduli increase with external stress. Increases in pore pressure cause an increase in bulk modulus but a decrease in shear modulus. The effect of using these determined effective moduli of fractured rock in modeling is investigated through a model of surface deformation over the In Salah gas reservoir in Algeria where carbon sequestration was performed. The In Salah CO₂ storage project is commonly studied due to the unexpected surface deformation observed. Surface deformation of less than a millimeter occurs from changing the material properties in this reservoir to that of saturated fractured rock containing 25 square rough fractures per cubic meter of 0.2 m side length and 0.22 m aperture, as determined in this study. / by Jamie Potter. / S.M. in Geophysics

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990. / Includes bibliographic references (leaves 262-272). / by Karl John Ellefsen. / Sc.D.